I have a 94 940 (non-turbo). I recently started using it again as a daily driver. I have the 19.8 gallon take, only got about 325 miles out of it, 16.4 i think per gallon. check engine light has come on so after pulling the code i got 2-2-1, which i stated in the title is for the heated O2. My question is where do i Go from here? how many O2 sensors are on the 940? Could this be why My MPG is so bad?? and i should note it is both highway and city/suburbs driving. any direction from here would be greatly appreciated. thanks



update. i recently read that it could be from an air leak/low fuel pressure/bad AMM??

 

Is this a BOSCH LH system? I don't know much about the 940's ... but that code is suggesting a lean mixture. I would listen for any vacuum leaks and look for any split or disconnected lines. It could also be the injector seals or the intake manifold gasket.

 

940 has one o2 sensor in front of the catalytic converter and it can affect mileage considerably. You may replace it with a generic one, less $ than Volvo, with splicing the wires. Check whether you have Regina or Bosch system-on your car it may be either--the two use different sensors.

 

thanks for the input yea its the non-regina (bosch) system. But i just dont want to replace the sensor if thats not it. How would i test it? And il also check thfor vaccum leaks thanks again.

 

Trace the O2 sensor wires back to where one plugs into the big green(?) wire on the firewall and peel back the rubber boot ... measure that wire while connected, during idle. It should swing quickly between .2 and .8VDC.

 

Well i tested the 02 and it is working. I also replaced my intake man. gasket. cleared the code. it was off for a while but is now back on with the same code... and other ideas?

 

The O2 sensor is a consumable item, if you have no documentation of it being replaced, you should replace it anyway, they make a HUGE difference to general running and fuel economy.
Buying a genuine Bosch one is cheaper than Volvo, but more expensive than the low budget O2 sensors, some of which I have had issues with on various cars over the years.
Do you have any other running issues at al? Anything, even small, could help pinpoint an issue.

Regards, Andrew.

 

The only thing I could say is that the car doesnt seem to flow smooth. when driving and going up threw the rpms it just seems like its lagging or sputtering but only slightly noticeable.. And i will try to get a bosch sensor this week. other than that no other codes. and fyi plugs and wires cap n rotor all reaplaced about a year and a half ago. new fuel pump last year.